You know very well how much I emphasize the longterm neurocognitive impairment following COVID-19 in SOME patients (not all, luckily!).
Many of these patients have normal brain MRI and they are told “you see, MRI is normal, so this is a psychological problem”. THe reason? Brain MRI studies the structure of the brain, which is normal most of the times, but not the function. A recent study further confirm this, showing that individuals recovering from COVID-19 continue to experience cognitive complaints, psychiatric and neurological symptoms, and brain functional alteration. The resting-state functional magnetic resonance imaging (rs-fMRI) results indicated that the changes in brain function in regions such as the putamen, temporal lobe, and superior parietal gyrus may contribute to cognitive complaints in individuals with long COVID even after 2-year infection.
Fifty-two survivors 27 months after infection (mild-moderate group: 25 participants, severe-critical: 27 participants), from our previous community participants, along with 35 healthy controls, were recruited to undergo fMRI scans and comprehensive cognitive function measurements. Participants were evaluated by subjective assessment of Cognitive Failures Questionnaire-14 (CFQ-14) and Fatigue Scale-14 (FS-14), and objective assessment of Montreal Cognitive Assessment (MoCA), N-back, and Simple Reaction Time (SRT). Each had rs-fMRI at 3T. Measures such as the amplitude of low-frequency fluctuation (ALFF), fractional amplitude of low-frequency fluctuations (fALFF), and regional homogeneity (ReHo) were calculated.
Compared with healthy controls, survivors of mild-moderate acute symptoms group and severe-critical group had a significantly higher score of cognitive complains involving cognitive failure and mental fatigue. However, there was no difference of cognitive complaints between two groups of COVID-19 survivors. The performance of three groups was similar on the score of MoCA, N-back and SRT. The rs-fMRI results showed that COVID-19 survivors exhibited significantly increased ALFF values in the left putamen (PUT.L), right inferior temporal gyrus (ITG.R) and right pallidum (PAL.R), while decreased ALFF values were observed in the right superior parietal gyrus (SPG.R) and left superior temporal gyrus (STG.L). Additionally, decreased ReHo values in the right precentral gyrus (PreCG.R), left postcentral gyrus (PoCG.L), left calcarine fissure and surrounding cortex (CAL.L) and left superior temporal gyrus (STG.L). Furthermore, significant negative correlations between the ReHo values in the STG.L, and CFQ-14 and mental fatigue were found. This means that the authors discovered correlations between cognitive function indices and spontaneous brain function, suggesting the presence of persistent brain abnormalities even after 2-year infection.
What are the implications?
The implications are huge.
As the authors state, “These findings provide valuable neuroimaging insights into the cognitive complaints of long COVID, thereby offering potential targets for treatment and intervention in individuals with brain fog of long COVID”. I would add that these findnigs also add for potential diagnostic tools for those patients complaining these symptoms and never trusted.
In my previous blogs you may have read how these findings are not new, but a confirmation. Even in a few pediatric studies we found similar brain PET abnormalities, like in this and this.
Thank you doctor for your unstoppable research for helping us 🙏🏻